Peptide Reconstitution & Dosage Calculators
Enter your vial size, BAC water volume, and desired dose to get the exact draw volume in syringe units — instantly. Free GLP-1 and peptide reconstitution calculators for BPC-157, TB-500, semaglutide, tirzepatide, retatrutide, MOTS-c, and more. Educational research tool, not medical advice.
Your mix
Syringe
Fill in vial size, BAC water, and dose to see your draw volume.
Educational research tools — not medical advice.
Or start with a compound
Pre-filled with common vial sizes and reference doses.
GLP-1 / Weight loss
Longevity / Metabolic
More peptide tools
All toolsHow the calculator works
Concentration formula
concentration (mcg/mL) = peptide (mg) × 1000 ÷ BAC water (mL)
Draw volume formula
draw (mL) = dose (mcg) ÷ concentration (mcg/mL)
syringe units = draw (mL) × 100 — U-100 convention
Smart fill algorithm
Iterates BAC water volumes from 0.5–5.0 mL in 0.25 mL steps, scores each by distance to the nearest 10-unit mark on the selected syringe, and returns the option that lands closest to a whole 10-unit increment within the syringe capacity.
All calculations are performed in the browser with full floating-point precision. Results are educational only — not dosing instructions.
Frequently asked questions
How do you calculate peptide draw volume?
Concentration (mcg/mL) = peptide amount in mg × 1000 ÷ BAC water volume in mL. Draw volume (mL) = desired dose in mcg ÷ concentration. Syringe units = draw volume × 100 (U-100 convention). For example: 5mg vial + 2mL BAC water = 2,500 mcg/mL. A 250mcg dose = 0.10mL = 10 syringe units.
How much BAC water should I add to a peptide vial?
Common volumes range from 1mL to 3mL depending on vial size and preferred dose volume. More BAC water means lower concentration and a larger draw per dose. Less BAC water means higher concentration and a smaller draw. Use the Smart Fill button to automatically find the BAC water volume that lands on a clean syringe mark for your dose.
What syringe size should I use for peptides?
Most peptide users choose a U-100 insulin syringe in 0.3mL, 0.5mL, or 1.0mL size. The 0.3mL (30-unit) syringe is ideal for small doses under 250mcg. The 1.0mL (100-unit) syringe covers larger doses. Select your syringe size in the calculator — it will warn if your draw volume exceeds the syringe capacity.
How many doses are in a peptide vial?
Doses per vial = floor(vial mass in mg × 1000 ÷ dose in mcg). A 5mg vial with a 250mcg dose yields 20 doses. A 10mg vial with a 500mcg dose yields 20 doses. The calculator displays this automatically after you enter your vial size and dose.